agent: Remove leftovers from IPv6 /96 prefix requirement
agent: Remove leftovers from IPv6 /96 prefix requirement

The requirement for the Kubernetes `-node-cidr-mask-size` to be a /96 has been
lifted a while ago but there were still some remaining leftovers hinting that
it exists. Remove them.

Fixes: #6804

Signed-off-by: Thomas Graf <5f50a84c1fa3bcff146405017f36aec1a10a9e38@cilium.io>

tgraf/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium,michi-covalent/cilium,tgraf/cilium,michi-covalent/cilium,cilium-team/cilium,cilium-team/cilium,tklauser/cilium,tklauser/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,tklauser/cilium,cilium/cilium